1 files changed, 194 insertions, 0 deletions
diff --git a/db2/include/lock.h b/db2/include/lock.h
new file mode 100644
index 0000000..18d29e8
--- /dev/null
+++ b/db2/include/lock.h
@@ -0,0 +1,194 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997
+ *	Sleepycat Software.  All rights reserved.
+ *
+ *	@(#)lock.h	10.7 (Sleepycat) 7/29/97
+ */
+
+typedef struct __db_lockobj	DB_LOCKOBJ;
+
+#define DB_DEFAULT_LOCK_FILE	"__db_lock.share"
+#define DB_LOCK_DEFAULT_N	5000
+#define DB_LOCK_MAXID		0x7fffffff
+
+/*
+ * The lock region consists of:
+ *	The DB_LOCKREGION structure (sizeof(DB_LOCKREGION)).
+ *	The conflict matrix of nmodes * nmodes bytes (nmodes * nmodes).
+ *	The hash table for object lookup (hashsize * sizeof(DB_OBJ *)).
+ *	The locks themselves (maxlocks * sizeof(struct __db_lock).
+ *	The objects being locked (maxlocks * sizeof(DB_OBJ)).
+ *	String space to represent the DBTs that are the objects being locked.
+ */
+struct __db_lockregion {
+	RLAYOUT		hdr;		/* Shared region header. */
+	u_int32_t	magic;		/* lock magic number */
+	u_int32_t	version;	/* version number */
+	u_int32_t	id;		/* unique id generator */
+	u_int32_t	need_dd;	/* flag for deadlock detector */
+	u_int32_t	detect;		/* run dd on every conflict */
+	SH_TAILQ_HEAD(lock_header) free_locks;	/* free lock header */
+	SH_TAILQ_HEAD(obj_header) free_objs;	/* free obj header */
+	u_int32_t	maxlocks;	/* maximum number of locks in table */
+	u_int32_t	table_size;	/* size of hash table */
+	u_int32_t	nmodes;		/* number of lock modes */
+	u_int32_t	numobjs;	/* number of objects */
+	u_int32_t	nlockers;	/* number of lockers */
+	size_t		increment;	/* how much to grow region */
+	size_t		hash_off;	/* offset of hash table */
+	size_t		mem_off;	/* offset of memory region */
+	size_t		mem_bytes;	/* number of bytes in memory region */
+	u_int32_t	nconflicts;	/* number of lock conflicts */
+	u_int32_t	nrequests;	/* number of lock gets */
+	u_int32_t	nreleases;	/* number of lock puts */
+	u_int32_t	ndeadlocks;	/* number of deadlocks */
+};
+
+/* Macros to lock/unlock the region. */
+#define	LOCK_LOCKREGION(lt)						\
+	(void)__db_mutex_lock(&(lt)->region->hdr.lock,(lt)->fd,		\
+	    (lt)->dbenv == NULL ? NULL : (lt)->dbenv->db_yield)
+#define	UNLOCK_LOCKREGION(lt)						\
+	(void)__db_mutex_unlock(&(lt)->region->hdr.lock, (lt)->fd)
+
+/*
+ * Since we will be keeping DBTs in shared memory, we need the equivalent
+ * of a DBT that will work in shared memory.
+ */
+typedef struct __sh_dbt {
+	u_int32_t size;
+	ssize_t off;
+} SH_DBT;
+
+#define SH_DBT_PTR(p)	((void *)(((u_int8_t *)(p)) + (p)->off))
+
+/*
+ * The lock table is the per-process cookie returned from a lock_open call.
+ */
+struct __db_lockobj {
+	SH_DBT	lockobj;		/* Identifies object locked. */
+	SH_TAILQ_ENTRY links;		/* Links for free list. */
+	union {
+		SH_TAILQ_HEAD(_wait) _waiters;	/* List of waiting locks. */
+		u_int32_t	_dd_id;		/* Deadlock detector id. */
+	} wlinks;
+	union {
+		SH_LIST_HEAD(_held) _heldby;	/* Locks held by this locker. */
+		SH_TAILQ_HEAD(_hold) _holders;	/* List of held locks. */
+	} dlinks;
+#define	DB_LOCK_OBJTYPE		1
+#define	DB_LOCK_LOCKER		2
+	u_int8_t type;			/* Real object or locker id. */
+};
+
+
+#define dd_id	wlinks._dd_id
+#define	waiters	wlinks._waiters
+#define	holders	dlinks._holders
+#define	heldby	dlinks._heldby
+
+struct __db_locktab {
+	DB_ENV		*dbenv;		/* Environment. */
+	int		 fd;		/* mapped file descriptor */
+	DB_LOCKREGION	*region;	/* address of shared memory region */
+	DB_HASHTAB 	*hashtab; 	/* Beginning of hash table. */
+	size_t		reg_size;	/* last known size of lock region */
+	void		*mem;		/* Beginning of string space. */
+	u_int8_t 	*conflicts;	/* Pointer to conflict matrix. */
+};
+
+/* Test for conflicts. */
+#define CONFLICTS(T, HELD, WANTED) \
+	T->conflicts[HELD * T->region->nmodes + WANTED]
+
+/*
+ * Status of a lock.
+ */
+typedef enum {
+	DB_LSTAT_ABORTED,		/* Lock belongs to an aborted txn. */
+	DB_LSTAT_ERR,			/* Lock is bad. */
+	DB_LSTAT_FREE,			/* Lock is unallocated. */
+	DB_LSTAT_HELD,			/* Lock is currently held. */
+	DB_LSTAT_NOGRANT,		/* Lock was not granted. */
+	DB_LSTAT_PENDING,		/* Lock was waiting and has been
+					 * promoted; waiting for the owner
+					 * to run and upgrade it to held. */
+	DB_LSTAT_WAITING		/* Lock is on the wait queue. */
+} db_status_t;
+
+/*
+ * Resources in the lock region.  Used to indicate which resource
+ * is running low when we need to grow the region.
+ */
+typedef enum {
+	DB_LOCK_MEM, DB_LOCK_OBJ, DB_LOCK_LOCK
+} db_resource_t;
+
+struct __db_lock {
+	/*
+	 * Wait on mutex to wait on lock.  You reference your own mutex with
+	 * ID 0 and others reference your mutex with ID 1.
+	 */
+	db_mutex_t	mutex;
+
+	u_int32_t	holder;		/* Who holds this lock. */
+	SH_TAILQ_ENTRY	links;		/* Free or holder/waiter list. */
+	SH_LIST_ENTRY	locker_links;	/* List of locks held by a locker. */
+	u_int32_t	refcount;	/* Reference count the lock. */
+	db_lockmode_t	mode;		/* What sort of lock. */
+	ssize_t		obj;		/* Relative offset of object struct. */
+	db_status_t	status;		/* Status of this lock. */
+};
+
+/*
+ * We cannot return pointers to the user (else we cannot easily grow regions),
+ * so we return offsets in the region.  These must be converted to and from
+ * regular pointers.  Always use the macros below.
+ */
+#define OFFSET_TO_LOCK(lt, off)	\
+	((struct __db_lock *)((u_int8_t *)((lt)->region) + (off)))
+#define LOCK_TO_OFFSET(lt, lock) \
+	((size_t)((u_int8_t *)(lock) - (u_int8_t *)lt->region))
+#define OFFSET_TO_OBJ(lt, off)	\
+	((DB_LOCKOBJ *)((u_int8_t *)((lt)->region) + (off)))
+#define OBJ_TO_OFFSET(lt, obj) \
+	((size_t)((u_int8_t *)(obj) - (u_int8_t *)lt->region))
+
+/*
+ * The lock header contains the region structure and the conflict matrix.
+ * Aligned to a large boundary because we don't know what the underlying
+ * type of the hash table elements are.
+ */
+#define LOCK_HASH_ALIGN	8
+#define LOCK_HEADER_SIZE(M)	\
+	((size_t)(sizeof(DB_LOCKREGION) + ALIGN((M * M), LOCK_HASH_ALIGN)))
+
+/*
+ * For the full region, we need to add the locks, the objects, the hash table
+ * and the string space (which is 16 bytes per lock).
+ */
+#define STRING_SIZE(N) (16 * N)
+
+#define LOCK_REGION_SIZE(M, N, H)					\
+	(ALIGN(LOCK_HEADER_SIZE(M) +					\
+	(H) * sizeof(DB_HASHTAB), MUTEX_ALIGNMENT) +			\
+	(N) * ALIGN(sizeof(struct __db_lock), MUTEX_ALIGNMENT) +	\
+	ALIGN((N) * sizeof(DB_LOCKOBJ), sizeof(size_t)) +		\
+	ALIGN(STRING_SIZE(N), sizeof(size_t)))
+
+#ifdef DEBUG
+#define	LOCK_DEBUG_LOCKERS	0x0001
+#define	LOCK_DEBUG_LOCK	 	0x0002
+#define	LOCK_DEBUG_OBJ	 	0x0004
+#define	LOCK_DEBUG_CONF	 	0x0008
+#define	LOCK_DEBUG_MEM	 	0x0010
+#define	LOCK_DEBUG_BUCKET	0x0020
+#define LOCK_DEBUG_OBJECTS	0x0040
+#define	LOCK_DEBUG_ALL	 	0xFFFF
+
+#define	LOCK_DEBUG_NOMUTEX	0x0100
+#endif
+
+#include "lock_ext.h"